No, you cannot smell carbon monoxide itself. It is colorless , odorless, and tasteless, which is why it is often called the “silent killer.”

What people sometimes do smell during a CO problem are other combustion byproducts that come with it, such as:

  • Exhaust‑type smells from furnaces, boilers, water heaters, or car exhaust seeping inside.
  • Rotten‑egg or sulfur smells from natural gas leaks (this is an added chemical called mercaptan, not carbon monoxide).

Because your senses cannot reliably detect CO, safety experts strongly recommend:

  1. Installing certified carbon monoxide detectors on every level of your home and near sleeping areas.
  1. Having fuel‑burning appliances (furnace, gas stove, water heater, fireplace) inspected regularly.
  1. Never running vehicles or fuel‑burning tools in enclosed or attached spaces, like garages.

If you ever suspect carbon monoxide exposure—symptoms like headache, dizziness, nausea, weakness, or confusion, especially if more than one person feels sick at the same time—leave the building immediately, get fresh air, and call emergency services.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.